This invention relates generally to products useful for home laundering, and more particularly to adjustable strength bleaching compositions, highly advantageous packaging of such compositions, and a method of bleaching involving the combination of the two. More specifically the invention relates to a home laundering composition containing a fabric-safe peroxygen bleach and an accompanying bleach activator system providing a convenient and effective means of achieving stronger bleaching action whenever desirable. The peroxygen bleach activated system of the invention takes advantage of the discovery that substantial concentrations of chlorides may coexist with a peroxygen bleach such as a monopersulfate without formation of effective amounts of hypochlorite, but with the addition of lesser amounts of bromides the combined halides participate synergistically in forming hypohalites in effective concentrations. More specifically, a laundry detergent system in accordance with the invention embodies a detergent containing a peroxygen bleach and which is safe for use on the majority of washable fabrics, together with a separate bleach activator system employing a synergistic combination of halide salts, part of which may be incorporated in the detergent, with the balance to be selectively added to effect stronger bleaching action.
Typical laundry wash temperatures in the United States continue to decline for various reasons; and with them, the bleaching ability of the oxygen bleaching agents in conventional all-fabric safe bleaches (e.g. sodium perborate). Such agents remain in wide use despite this fact, because of their efficacy at elevated temperatures, and their virtual inability to harm sensitive fabrics and dyes, regardless of the washing conditions. Chlorine bleaches on the other hand, though very potent even at low temperature, are well known to affect adversely many colored fabrics, and they often substantially reduce the efficacy of many fluorescent whitener agents contained in most detergent products.
The ability of peroxymonosulfate to oxidize halides to hypohalites and hypohalous acids; and to consequently boost the overall bleaching effectiveness, is well known in the industry. See U.S. Pat. No. 458,446; French Pat. No. 1,568,919; German Pat. No. 1,269,992, and U.S. Pat. No. 1,162,754.
There is also substantial prior art concerning methods of reducing fabric degradation when using a sodium bromide activated bleach. German Pat. No. 2,525,878 (see also U.S. Pat. No. 4,116,878) issued to Fritz Deutscher in January of 1976 teaches that textile degradation can be minimized by adding urea-or acetamide to a sodiumbromide activated peroxymonosulfate bleach. U.S. Pat. No. 4,123,376 issued to Frederick W. Gray in October of 1978 teaches that certain (other) N-hydrogen compounds inhibit destruction of dyes and overbleaching of dyed materials when used in a sodium bromide promoted peroxymonosulfate bleach composition. U.S. Pat. No. 4,028,263 issued to Frederick Gray in June of 1977 discloses certain flourescent whitening agents which are relatively stable in such a system for use in a detergent/bleach composition. Each of these patents refers only to bleaching enhancement from bromide ion addition, with no mention of the synergism and possible toxicity conditions which result from using a combination of chloride and bromide salts.